For years scientists searched fruitlessly for the causes of autism by looking for genes shared by families prone to the disorder. Now researchers taking a new approach have begun to unlock its secrets.

In 1998, the landscape photographer Richard Misrach roamed Louisiana to document a legacy of its petrochemical industry. In a series of stark photographs, he captured how the infrastructure of oil, gas, and chemical companies dominates the environment, running through waterways and open spaces and looming over neighborhoods. The photos seen here, along with others by Misrach, formed the basis of a 2012 book, Petrochemical America, in which the landscape architect Kate Orff also mapped the environmental damage wrought by the industry. Misrach’s photos serve as a reminder of how widely the petrochemical business encroaches, well beyond the sites where oil and gas are pulled from the earth.